REED B50HPG, Technical Manual, Page: 20 / 235

OPERATION and MAINTENANCE
Rev 1.2 19 of 80
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solenoid operation. Its purpose is to direct the flow of oil from the main hydraulic pump
to one or the other
To energize the pump circuit, use the RPM button to set the engine speed at maximum
RPM. Open the VOLUME control to any range from 0 to FULL. In so doing, the load
sense is alerted to the demand and places the pump on stroke. The pump will now
produce the flow in proportion to the amount by which the volume control has been
opened. Since the PUMP switch is OFF, the flow from the hydraulic pump is fed to the
main directional valve, thru the valve, and then returns to the hydraulic tank.
To energize the cycling circuit, the PUMP switch must be ON. When this is done, an
electrical signal is generated which in turn energizes the coils of the main directional pilot
valve and activates the S-Tube directional valve.
The material pumping action is the result of the two material cylinders cycling on an
alternate basis. This alternating cycling is controlled by an electrical signal that is
generated by the proximity sensors located in the flush box at the end of each material
cylinder’s suction or retraction stroke.
As the piston coupler passes under the proximity sensor, it generates an electrical input
signal that is sent to the logic controller, designed to control the alternating action of the
material cylinders and to synchronize the movement of the s-tube. The output signal from
the logic controller is used to energize the coils of the main directional pilot valve as well
as that of the s-tube directional valve.
As protection to the main pump circuit against excessive pressure, a relief valve has
been installed and set. Thus, when the system pressure reaches the maximum factory
settings, the relief valve opens directing the oil back to the tank.
MATERIAL
OIL
PROX SIGNAL